JPS62109836A - Production of preexpanded polystyrene based resin particle - Google Patents

Abstract

PURPOSE:To produce preexpanded particles, uniformly coated with a very small amount of a treating agent and hardly causing bridging, by atomizing a treating agent with a pressurized air for feeding preexpanded particles through a duct to a silo and bringing the atomized treating agent into contact with the preexpanded particles. CONSTITUTION:Resin particles are fed from a raw material hopper 1 to a preexpanding machine 3 by a screw feeder 2 and preexpanded particles are fed through an outlet 5 of a preexpanding tank 4 and hopper 6, passed through a pneumatic feeding duct 7 and pneumatically fed to an aging silo 8 while suspensed with a pressurized gas supplied from a particle feeding blower 9. In the stage, a spray nozzle 22 is placed in the interior of the pneumatic feeding duct 7 to atomize the treating agent emerging from the spray nozzle 22 with the pressurizing gas from the particle feeding blower 9 to coat the preexpanded particles with the treating agent in the flow of the atomized treating agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing pre-expanded polystyrene resin particles coated with a treatment agent, and in particular,
The present invention relates to a method for producing pre-expanded particles that can be uniformly coated with a treatment agent of t and has less bridging.

Pre-expanded particles of polystyrene or f-resin are placed in a container and heated and cooled to produce a foamed molded product. For 1-1 purposes such as shortening the 7J+ cycle), use pre-expanded particles whose surfaces are coated with a treatment agent such as fatty acid amide, aliphatic amine, fatty acid metal salt, paraffin oil, polyethylene wax, etc. It has been known.

Known coating techniques using the above-mentioned processing agents include the following methods.

■Processing of the pre-foamed 11 particles; Put the resin particles and the processing agent into a mixer such as a ribbon blender and mix.

■Processing during pre-foaming: A processing agent is fed into a screw feeder that transports resin particles into a pre-foaming tank, and steam foaming is performed in the tank.

■Processing after foaming: The foamed particles and processing agent are placed in a mixer such as a Riphon blender and mixed.

However, each of the conventional processing methods described above has the following problems.

In the case of ■, have the resin particles been coated? LPfi
Since it takes time to carry out the foaming treatment, there is a possibility that the surfaces of the resin particles may be altered depending on the treatment agent such as fatty acid amide F. Furthermore, since the coating process is mixed using a separate mixer, it cannot be carried out continuously with the pre-foaming process, which is time consuming and inefficient.

In the case of (2), the mixing is done using a screw feeder, and the amount of processing agent added is 0.01 to 1 part per weight of the resin particles. %, the residence time in the mixing zone must be increased, and the mixing efficiency is very low compared to when using a normal mixer.

When the processing agent is a powder, it must be used by dissolving it in a large amount of solvent or dispersing it in water or the like to form an emulsion, and the influence of the solvent or dispersion medium becomes a problem.

If the resin particles fed into the pre-foaming tank contain a treatment agent in solution, the amount of drainage in the foaming tank will increase and the wetness of the pre-foamed particles will increase.

Wetness of the pre-expanded particles can be caused by poor filling when filling the pre-expanded particles into the special mold cavity, or by bridging phenomenon in the maturing silo of the pre-expanded particles. This may cause delivery failure.

For this reason, a device for drying the pre-expanded particles is required.

Furthermore, according to method (2) above, it is difficult to uniformly coat the entire surface of the resin particles with the treatment agent, and the coating tends to be localized, so there is also the problem that bridging of the expanded particles occurs frequently.

In the case of (2), the volume of the pre-expanded particles is 20 to 60 times larger than that of the resin particles of the foamed Iiη, so a mixer with a large capacity is required, and the work becomes extensive.

Furthermore, it is nearly impossible to uniformly coat the entire surface of the pre-expanded particles whose surface h1 has expanded with a fine amount of treatment agent. As can be understood from the above-mentioned conventional examples and their problems, coating with a processing agent requires (1) uniform coating of a small amount of the processing agent on the pre-expanded particles, and treatment by adhesion to the tank wall surface, etc. The following problems must be solved at the same time: (II) preventing the occurrence of bridging, etc. caused by the coating of the processing agent.

17. However, when considering the conventional coating methods mentioned above, they have in common that they rely on a tlJ combination-L stage using a /lJ combination device such as a mixer or a screw feeder.

Therefore, it is not a good idea to follow the conventional mechanical 7F9 method as a means of efficiently coding the processing agent of the kick. On the other hand, since the resin particles to be coated are q-objects, the only way to uniformly coat all of them is to rotate the particles or immerse them in a treatment agent. do not have.

As a result of research, the present invention has been developed by atomizing a processing agent and bringing it into contact with resin particles, and by placing the resin particles in the flow of the atomized processing agent, and thereby achieving the "0.
I learned that I didn't have to take the dan (+!).

The present invention is based on such technique i41];[b made at 1°b, and its purpose and purpose is to coat the cypress oil particles by atomizing the treatment agent. At the same time as achieving uniform coating with the treatment agent of CHI M,
The purpose is to prevent bridging between particles.

In the manufacturing process of polystyrene resin pre-foaming, such coating treatment may be carried out either before or after the pre-foaming process, but preferably after the pre-foaming process.
I! It is preferable to realize this at the stage of supplying steam to the resin particles in the I tank or at the stage of air transporting the pre-expanded particles after pre-foaming to a maturing silo.

Here, prior to the description of Examples, an apparatus for producing pre-expanded polystyrene resin particles of the present invention will be described. In FIG. 1, 1 is a raw material hopper for polystyrene foam particles, and 2 is a screw feeder, which feeds resin particles from the raw material hopper 1 to a -f-equipped foaming machine 3. 4 is a foaming tank f, 5 is a foamed grain-r outlet provided in its first part; 1.6 is a hopper for pre-foamed grains, and 7 is a hopper 6.
This is an air transport duct that transports the pre-expanded particles supplied from the silo to the aging silo 8. The end of the air feeding duct 7 on the side of the hopper 6 is connected to a particle feeding blower 9, and this particle feeding blower 9 transfers the Pi expanded particles supplied from the hopper 6 into the air feeding duct 7 to The material is air-fed to the silo 8 while being suspended by pressurized gas.

The resin particles are supplied with steam in the foaming slide 4, and at this time, coating is performed by supplying a treatment agent into the steam and atomizing the treatment agent, as described below. . This is a method disclosed in Japanese Patent Application No. 56268/1983.

1- That is, this method uses sorbitan monopalmitate (alcoholic solution, same in the following examples) as a processing agent, and the sorbitan monopalmitate is atomized and the steam is used as the first stage. This is an example using . As shown in FIGS. 1 and 2, resin particles are fed to the lower part of the pre-foaming tank 4 by a screw feeder 2,
A treatment agent coating device A1 is installed in the steam duct 11 that supplies steam S to the resin particles in the pre-foaming tank, and solhitan monostearate, which is a treatment agent, is applied to the slurry 4 on the steam flow. Supply "l-ru."

The processing agent coating device A includes a spray nozzle 12 (FIG. 3) arranged in a steam duct 11, and a processing agent supply r front 1 connected to the center seven nozzles 13 of the nozzles 12.
4, a steam supply pipe 16 connected to the annular nozzle 15 of the nozzle, a pressurized air system (not shown), and a treatment agent metering pump. In addition, the direction of the spray nozzle is set parallel to the flow direction of the steam S in the steam duct 11, and the 4D position of the spray nozzle is set in the steam duct 11.
It is in the center. In FIG. 2, 17 is a stirring blade for stirring the resin particles in the preliminary foam 51, and 18 is a so-called jammer rod.

In this coating method, sorbitan monopalmitate is atomized by steam S for foaming, and is dispersed and supplied into the flow of resin particles along with the steam flow.

The above is an example in which the processing agent is atomized by the steam used for pre-foaming, but in the embodiment of the present invention described below, the processing agent is atomized by pressurized air that feeds the pre-foamed particles to the maturing silo 8. This is an example of

〔Example〕

This example is an example in which the treatment agent from the Sbress nozzle 22 disposed inside the pneumatic duct 7 in the coating apparatus A2 of FIG. 1 is atomized by pressurized air and sprayed onto the pre-expanded particles. . The Sbress nozzle 22 is similar to that shown in FIG.
Place it in the center. FIG. 5 shows the entire structure of the coating apparatus A2, in which sorbitan monopalmitate as a treatment liquid is stored in a tank 23, and is sent to the spray nozzle 22 via a supply pipe 25 by a pump 24. The compressed air supply system supplies compressed air q'C
is sent to the spray nozzle 22 via channel 27.

In the above device A2, since the number of pre-expanded particles is -1- (also j5), the number of pre-expanded particles passing through the coating part of the air conveyance duct 7 is mixed with 111 of the expanded particles. An appropriate control method such as a quantitative method is adopted to match the ejection 111 of tanmonopalmidate.The pre-expanded particles and pressurized air flowing in the air conveyance duct 7 move in a complicated manner, and the spray Since sorbitan monopalmitate is supplied from the nozzle 22, it is atomized by the pressurized air, mixed and diluted in the air, and uniformly adheres to the surface of the pre-expanded particles.

Note that although the above examples only exemplify the atomization method using a nozzle similar to a spray gun, the manufacturing method of the present invention is not limited to this example, and the atomization method using pressurized turbulent flow is not limited to this example. It is also possible to atomize using the Hentschli effect or the Hentschli effect, or a combination of these. Further, the processing agent may be a fatty acid amide, a fatty acid metal salt, paraffin oil, or the like.

As explained above, according to the present invention, the location Fl! Since the liquid is atomized, there is less loss due to adhesion to the tank wall, etc.
Furthermore, the treatment agent @:1 enables uniform coating on the entire surface of the pre-expanded particles.

Further, since a uniform coating is applied to the entire surface of the particles, bridging of the particles -r can be prevented from occurring.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing an apparatus for producing pre-expanded polystyrene resin particles of the present invention, Fig. 2 is a plan view of a processing agent coating device A and a pre-expanding machine, and Fig. 3 is a viscous spray similar to Fig. 2. FIG. 4 is a sectional view of a nozzle, FIG. 4 is a perspective view of a spray nozzle used in an embodiment of the present invention, and FIG. 5 is a perspective view of a pressurized air supply device in an embodiment.

Claims (1)

[Claims] In a method for producing pre-expanded particles by pre-expanding expandable polystyrene resin particles, the pre-expanded particles include:
A method for producing pre-expanded polystyrene resin particles, characterized in that the particles are coated in the duct with a treatment agent atomized by pressurized air that is sent to the silo through the duct.